The present invention relates to safety barriers for road use of the type comprising at least one barrier element and a supporting structure for supporting the barrier element, provided with means for anchoring thereof to the ground, wherein said supporting structure is movable between a first position, in which the barrier element is in an operative position above the road surface, and a second position, in which the barrier element is in an inoperative position in which it does not substantially project above the road surface, wherein in said inoperative condition the barrier element is received inside a trench formed in the road surface, wherein the supporting structure includes at least one supporting column articulated at one of its ends to a bracket for anchorage to the ground and, at the opposite end, to the barrier element, said supporting column being pivotable between an operative upright position and an inoperative lowered position, and in which means are provided for controlling rotation of said supporting column.
A road barrier of the above indicated type is disclosed in document DE-A-34 20 503. In this known solution, more barrier elements are provided which, when in the lowered position, are spaced apart from each other, so that free spaces are defined therebetween which require the provision of additional platforms in order to cover the trench which receives the barrier elements in the lowered condition. Moreover, in this known solution, in case only some of the barrier elements are lowered into the inoperative position, interruptions are formed at the areas interposed between each lowered element and an adjacent raised element. Finally, the solution shown in the above indicated document has a structure such that any operations for replacing a damaged barrier portion, for example due to a road accident, become lengthy and troublesome.
The same drawbacks are encountered also in the barrier shown in document FR-A-2 750 148. In particular, although this solution shows a barrier with a connecting element which connects a retractable barrier element to a non-retractable barrier element, it does not provide for a connecting element between two barrier elements which are both retractable, so that there are not ample possibilities to choose the barrier portion which one wishes to retract. Furthermore, the barrier of this second known solution does not ensure a continuous surface both above and on the two sides of the barrier and moreover it has columns for supporting the retractable element which are directly articulated to the walls of the trench in which the retracted element is received, so that any operations for replacing a damaged barrier element are lengthy and costly.